It is legal to cut a barrel down as long as it is no shorter than 18". I would cut it no shorter than 18.5" to be on the safe side. Also if it ever gets the muzzle damaged you will have some extra barrel length to repair it.

You can order a 18.5" 835 barrel from Mossberg. You will have to call them to get one.

Other options are: The Mossberg 500 Tactical Breacher barrel and the LE 590A1 18.5" barrel will fit the 835 shotguns. These are 3" chamber barrels and you can only fire up 3" shells, no 3.5" shells.

These two companies have the exclusive on the Mossberg 500 Tactical Breacher barrels. No one else carries them.

Look at the pictures I posted above of the 590A1 18.5" and the 500 Tactical Breacher shotguns. You can see the barrel lug ring is the same as on your 835.

Don't confuse the Mossberg 500 Tactical Breacher shotguns with the standard 500 shotguns. They are not the same.

The standard Mossberg 500 barrels will not fit the 835 because they have a different mag tube setup. The 835, 500 Tactical Breacher, 500 MilsGun (Special Military shotgun) and the 590A1 with a 18.5" barrel only, not the 20" barrel 590, have the same mag tube setup so the barrels and mag tube extensions will interchange.

The 835 has a 3.5" chamber.

The 590A1 18.5" and 500 Tactical breacher barrels have a 3" chamber. If you install one on a 835 you can't shoot 3.5" shells out of it, only 2 3/4" & 3" shells.

The only way you can cut the barrel is if the length of the barrel is NOT stamped on the barrel. Otherwise you own a WMD and that is not good to get caught with.as to the 500 Breacher barrel I wouldn't. Sell the 835 and get a 500. You also have to make sure the 26in. length requirement is met for long guns.